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2-7
The amplifier has fast acting sophisticated protection circuits. Please note,
however, any such actions that cause the same fault to occur repeatedly, will lead
to failure of the valuable final power FET transistors.
2-8
Before checking inside the amplifier, be sure to wait a few minutes for the high
DC voltage to discharge (monitor Vd meter reading). The potentiometers for RF
power detector, protection circuits, FET bias voltage circuit, etc., are precisely
adjusted at the factory, and should not be altered. Doing so, would require
readjustment with precision measuring instruments.
2-9
The DC power supply section consists of most efficient and sophisticated
switching mode circuit. It accepts the wide AC line voltages ranging from AC
100V up to 260V. Since the line voltage is detected and selected automatically,
you do not have to worry about the tap change of internal power transformer
whichever country you will travel. Be sure to verify capacity of AC line fuse
before you plug the AC power cord into the outlet.
2-10
Before starting the amplifier, be sure to connect a dummy load (50 ohms, 550W
min.) or a well-adjusted antenna to the output terminal. Operating without any
load will cause extreme stress to the RF power FET's, although protection
circuits should work under critical conditions.
2-11
Required drive power is slightly less than 100W to obtain the full 550W output.
Do not attempt to operate with excessive drive from a high power transceiver.
2-12
Keep the aluminum heat sink and air openings free from dust and blockages.
Periodic cleaning will prevent degraded cooling efficiency.
2-13
For long continuous operation in RTTY/FM modes, it is recommended that you
reduce the RF drive levels by 20% to 30% lower output than CW/SSB modes.
2-14
To prevent damage to the precision electronic components, avoid extreme
physical shock to the amplifier. If factory service is required, the amplifier should
be shipped using the original box and packing materials.
2
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